Heavy metal veterans Black Sabbath have announced they are reuniting, more than three decades after the release of their last studio album.

In a much-hyped appearance at Hollywood's Whisky A Go Go club on Friday , the band's original line-up told an ecstatic gathering of fans they would be bringing out their first new studio album in 33 years in 2012. As well as the record, to be produced by Rick Rubin, the band will also be embarking on a worldwide tour after headlining Download Festival in their native Midlands next year.

Ozzy Osbourne joined fellow sexagenarians Tony Iommi, Geezer Butler and Bill Ward at the venue where the band made their Los Angeles debut in 1970, to address a large, black-t-shirt-clad crowd.

Metal Hammer magazine reported an "electric" atmosphere as the hour of the announcement approached.

The comeback sparked jubilation among fans, many of whom had long hoped to see the Birmingham rockers reunite.

James McMahon, editor of Kerrang! magazine, insisted the reunion did not represent just another bunch of old timers getting back together to cash in on their cult status, and predicted fans would feel the same way. "Metal fans can be the most cynical people in the world," he said. "But the return of Black Sabbath – I don't think anyone thinks that's a bad thing.

"It's different because they announced they're making a record and that's really exciting. It doesn't feel weary in the way a lot of reunions of classic bands does.

"They are the Beatles of heavy metal. It all starts with Black Sabbath."

Murmurs of a reunion circulated earlier this year following reports of secret rehearsals as well as album and touring plans. Iommi was quick to scotch the rumours, dismissing them as "speculation", although not denying them outright.